65 W of average power and 6-MW peak power generation from a mode-locked fiber oscillator

We report on the generation of femtosecond pulses from an all-normal-dispersion fiber laser featuring a large-mode-area ytterbium-doped photonic-crystal fiber. Nonlinear polarization evolution assisted by passive spectral filtering in combination with the large-pitch fiber design enables a significant peak power enhancement with the generation of multi-megawatt pulses. 65 W of average power at 76.5 MHz repetition rate, corresponding to 850 nJ pulses are generated in a compact oscillator setup. The output pulses are extra-cavity dechirped down to 111fs with 6 MW of peak power. To the best of our knowledge, these are the highest average and peak powers ever reached by a mode-locked fiber laser.